Plastic texture pack won't work. $4.49

Hi. My son bought the plastic texture pack and he played it for 4 mins and then he had to leave the house. When he got home he got on Minecraft and the texture pack was gone. I checked the settings and it said he never bought it, but the money is gone from his account. I have to authorise any purchases he makes and so I know that the process was followed and he did make the purchase. How does this get rectified? I look forward to your response. Kind regards Justin